Electrical connector



Feb. 2 8, 1939. A. H. SURPRENANT ELECTRICAL CONNECTOR Filed April 4,1938 v Jaye/Z101- ALBERT [7.5URPRENANT i W d Patented Feb. 28, 1939UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to electrical connectors, and more particularlyto connectors of the type having a socket adapted to receive a metalterminal prong and to be expanded by the insertion of such prong.Connectors of this type are commonly provided with two of these sockets,and they are used in conjunction with electric irons, toasters andsimilar appliances.

Since the sockets are usually formed of a metal which is selectedprimarily because of its good electrical conductivity, they ordinarilylack the resilience necessary to maintain a firm contact with the prong.The initially poor contact causes arcing of the electric current andresulting in heating and rapid deterioration of the metal parts. Thishas been recognized, and it has proposed heretofore to utilize varioustypes of steel springs to urge the socket parts into contact with theprongs, but in general these prior constructions have not provensatisfactory. In some cases the sockets have been complicated andexpensive, and the springs could only be applied in the course ofmanufacture. In other cases the springs fail to remain in operativeposition. With still other proposed constructions the socket partsbecome twisted or distorted when the prong is inserted, preventing firmcontact over a substantial area.

It is accordingly one object of the invention to provide a comparativelysimple and inexpensive socket which will expand readily to receive aprong inserted therein and which will ensure a firm low-resistanceelectrical contact with the prong.

It is a further object of the invention to provide a comparativelysimple and inexpensive socket of the type having a pair of opposedconductors between which a prong may be inserted, and a spring engagingthe conductors to urge them against the prong.

It is a further object of the invention to provide a simple andinexpensive spring adapted to fit a socket of the expansible type and toforce the socket parts into firm contact with an inserted prong.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

Referring to the drawing illustrating one embodiment of the inventionand in which like reference numerals indicate like parts,

Fig. 1 is a View of an electrical connector, partially broken away toshow the interior construction;

Fig. 2 is a greatly enlarged section taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2, showing the socket expanded by theinsertion of a cylindrical p Fig. 4 is a side elevation of a socket; and

Fig. 5 is a greatly enlarged perspective view of a spring.

The embodiment illustrated comprises a body ID of insulating materialformed in two separable parts which are held together by any suit ablemeans. This body [9 is recessed to receive a pair of spaced parallelsockets HH to which electric current may be supplied through atwoconductor cord [2. This cord may be supported by the usual flexiblesleeve l4 mounted at one end in the body In.

Each socket H comprises a pair of adjacent members Iii-l5 formed of asuitable sheet metal having good electrical conductivity, these membershaving flanges l6 along their lateral edges and central transverselycurved portions I8 formed with concave inner surfaces and convex outersurfaces, as shown particularly in Fig. 3, so that a cylindrical prongI9 may be inserted axially between the members to force them apart. Itwill be understood that a pair of these prongs I9 will be mounted inparallel positions upon the electric iron or other appliance to whichelectricity is to be supplied. As shown in Fig. 4, the two members |5I5for each socket may be formed from a single piece of metal doubled backupon itself, with a screw mounted therein near the folded end tofacilitate connection of the electrical leads thereto in a wellknownmanner. The free ends of the members l5 are flared, as indicated at 2|,to aid in the insertion of the prong.

In order to maintain adequate pressure between each socket and theinserted prong, and thus ensure a low-resistance electrical contact, Imount on each socket near the flared end 2| thereof a U-shaped spring 23formed of a suitable thin sheet metal, such as spring steel, having highstrength and resilience. As shown particularly in Fig. 5, each spring 23comprises a base portion 24 and two cantilever portions 25 extendingfrom the ends of the base portion at substantially right angles thereto.A curved portion 21 extends from each cantilever portion, the two curvedportions having concave inner surfaces located directly opposite eachother. The two cantilever portions 25 and the base portion 24 form aloop which connects the two curved portions 21, the cantilever portionsconstituting the legs of the loop. The free ends of the two branches ofthe spring are flared outwardly at 28, adjacent the curved portions 21,

In assembling the parts the spring 23 is forced over the socket II fromone side, the flared portions 28 facilitating this operation. The innerconcave surfaces of the spring portions 21 engage the outer convexsurfaces of the socket portions I8 and apply pressure to the members I 5from diametrically opposite points to force these members together, asindicated in Fig. 2. The

cantilever portions 25 of the spring are spaced from the flanges E6 onthe members if: so that these members may separate upon insertion of theprong l9, as shown in Fig. 3, without any lateral tilting or twisting ofthe members. At the same time, the spring is held in place on the socketlaterally and is prevented from turning thereon to any appreciableextent by the flanges IS.

The operation of the invention will now be apparent from the abovedisclosure. To effect an electrical connection, the body IE] will begrasped in one hand and the sockets II will be forced over the prongs 19of the particular appliance which is to be energized electrically. Theseprongs will force the members l5 apart, as shown in Fig. 3, the springs23 holding these members in firm contact with the prongs. The separationof the socket members I5 takes place evenly on both sides, without anytendency to tilt or twist these parts laterally. The construction of thesockets, as well as that of the springs, is comparatively simple andinexpensive. The springs can be readily placed over the sockets fromeither side, and will remain in proper posi tion thereon without anytendency toward lateral slipping.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. An electrical connector comprising a pair of adjacent members havingtheir inner surfaces concave and their outer surfaces convex, saidmembers forming a socket adapted to receive a cylindrical prong whichmay be inserted axially between said members to force them apart, and aU-shaped spring having two opposed inwardly concave curved portions anda loop portion connecting said curved portions, the said curved portionsengaging the outer convex surfaces of the two members respectively atdiametrically opposite points to urge said members together and to holdthe spring in position thereon, the legs of the loop portion of thespring being spaced from the outer surfaces of said members sufficientlyto allow expansion of the socket upon insertion of the prong withoutlateral tilting or twisting of said members.

2. An electrical connector comprising a pair of adjacent members havingtheir inner surfaces concave and their outer surfaces convex, saidmembers forming a socket adapted to receive a cylindrical prong whichmay be inserted axially between said members to force them apart, and aU-shaped spring having a base portion, two cantilever portions extendingfrom the base portion, and an inwardly concave curved portion extendingfrom each cantilever portion, the said inwardly concave curved portionsengaging the outer convex surfaces of the two members respectively atdiametrically opposite points to urge said members together and to holdthe spring in position thereon, the cantilever portions adjacent to thebase portion being spaced from the outer surfaces of said-memberssufiiciently to allow expansion of the socket upon insertion of theprong without lateral tilting or twisting of said members.

3. A spring for an electrical connector comprising an imperforate baseportion, two cantilever portions extending from the ends of the baseportion at substantially right angles thereto, and

a curved portion extending from each cantilever portion, the two curvedportions having concave inner surfaces located directly opposite eachother, the spring being formed of spring steel of uniform thicknessthroughout.

ALBERT H. SURPRENANT.

